In a typical situation, a tractor of a heavy truck rig provides braking power and electric power to the trailer. The tractor has a pneumatic power braking system connected to a braking system of the trailer. This pneumatic system has one or more fluid pressure outlets with hoses connected thereto. These hoses transmit the effects of the fluid pressure of the braking system of the tractor to the braking system of the trailer so both systems function simultaneously. Power for the lighting system on the trailer also is provided by an electric cable from the tractor.
Basically, three types of heavy tractors used in the United States are the cabover, the slip cab and the conventional cab. The slip cab includes a flat nose cab wherein the entire driver cabin rotates forwardly in order to allow access to the engine. The cabover is a slip cab with a sleeper. The conventional tractor has a hood somewhat like an automobile and may also have a sleeper. Each of these tractors has air hoses for coupling the tractor braking system to the trailer braking system, and an electric cable to provide power for the trailer lighting system.
Due to the flexibility between the tractor and the trailer pulled by the tractor, it is necessary for the tractor to carry a reasonable amount of excess hose and cable, in order to compensate therefor. This excess hose and cable cause problems both when in use with a trailer and when not in use. When the tractor is without a trailer (commonly known as bobtail) the hoses and cable hang loosely in racks on the truck or are otherwise displayed. With such a display, the hoses rub together unnecessarily, and the resulting friction causes damage to the hoses.
This wear on the hoses makes them extremely dangerous. The hoses have to be changed regularly as a safety precaution. Such changes are an expensive and a time consuming undertaking. However, if the hoses fail, the trailer brake system fails. If the trailer brake system fails the brakes lock up and the truck can be involved in an accident which could be extremely costly in terms of material damage and injuries. The hoses can also be damaged and weakened by stress, such as can be caused by sharply turning.
Additionally, the dangling hoses and cable are unsightly. With the hoses and cables entangled as is encouraged by the free hanging nature thereof, a problem is created for the driver who must first untangle and separate the hoses and cables before they can be used. The hoses also thump against the cab which can cause an annoyance to the driver. The crimping of the hoses and cable can also contribute to weakening and premature failure of the hoses.
Additionally, it is common for brake lines to acquire moisture therein and freeze--especially during the winter. In fact, the brake lines can even freeze while in use. This freezing problem is magnified with rail piggyback trailers, or a plurality of trailers in a lot, which are moved constantly. A sitting trailer freezes the hoses more easily than does a moving trailer. So anyone in a drop and switch operation can run into problems with a frozen hose. It is desirable to avoid this freezing aspect and the resultant damage therefrom. If this damage can be avoided, great advantages can be obtained.